The heart and head of each, what screen

Was broken there to give them light,

While in ourselves it shuts the sight,

We should no more admire, perchance,

That these found truth out at a glance,

Than marvel how the bat discerns

Some pitch-dark cavern's fifty turns,

Led by a finer tact, a gift

He boasts, which other birds must shift

Without, and grope as best they can."